This invention relates generally to electric motors and more specifically to means for mounting motor starters, protectors and capacitors for use with split phase electric motors.
Room air conditioners, particularly for refrigeration compressors, typically comprise an hermetic enclosure in which is contained an evaporator, condenser, motor and other related components. The motor, conventionally a single split phase motor having a main winding and an auxiliary winding, is energized through three conductive pins disposed in a glass header mounted in a wall of the enclosure. Within the enclosure the pins are coupled to the main and auxiliary windings. Outside the enclosure it is conventional to mount a motor starting device, a motor protector and, depending upon torque, noise and efficiency requirements, a capacitor. That is, the main and auxiliary windings have different ratios of inductive reactance to resistance and are connected in parallel to magnetize the core of the motor. Line current is split into two parts so that a time displacement of thirty or more electrical degrees exist between them. To provide different starting torque and mechanical (noise) performance characteristics there are both standard and capacitor motors in common use. Capacitor motors are further divided as capacitor start, permanent-split capacitor and two value capacitor motors. Further variations include capacitor start induction run and resistance start capacitor run using a positive temperature coefficient resistor for starting. Each type has its own characteristics with regard to starting or running torque, noise and efficiency.
Split phase motors are used in a wide variety of applications in addition to refrigeration compressors such as, by way of example, room air conditioners, freezers, blowers and fans, washing machines, centrifugal pumps, etc. Depending on the requirements of the particular application anyone of the above noted split phase motors could be employed, each having special handling requirements, sizing, wiring and locating considerations.